1. Field of the Invention
This invention relates to an electrical connector, and more particularly, relates to an electrical connector for holding a chip module to connect the chip module to a circuit board.
2. Description of the Prior Art
As shown in FIGS. 1 through 3, an electrical connector for holding a chip module D to connect the chip module D to a circuit board in the prior art includes a body A, a cover B on the body A, and a driving device C for driving the cover B to move on the body A.
The body A has a first rectangle hole A1 and an area A2 for conducting and accommodating solder between the first rectangle hole A1 and the edges of the body A. A plurality of terminal holes A21 are formed at the area A2 for conducting and accommodating solder. Each of the terminal holes A21 accommodates a terminal A22 and a tin ball A23. The tin ball A23 is exposed out of the bottom surface A3 of the body A.
The cover B is used for holding the chip module D. The cover B has a second rectangle hole B1 corresponding to the first rectangle hole A1 and an area B2 for accommodating pins between the second rectangle hole B1 and the edges of the cover B. A plurality of pin holes B20 are formed at the area B2 for accommodating pins.
After the electrical connector is assembled completely, the cover B could move on the body A under the driving by the driving device C. The pin holes B20 at the area B2 for accommodating pins correspond to the terminal holes A21 at the area A2 for conducting and accommodating solder one to one. The second rectangle hole B1 lies above and communicates with the first rectangle hole A1, for accommodating a corresponding structure on a circuit board. The second rectangle hole B1 has a first rim B11 and a second rim B12 parallel to each other and a third rim B13 and a fourth rim B14 parallel to each other. The four rims protrude upwards from the surface of the area B2 for accommodating pins, which acts the function of supporting the chip module D. In view of a symmetric structure bringing a uniform supporting force, the second rectangle hole B1 is usually designed to be a square hole and the center thereof lies at the center of the area B2 for accommodating pins. Thereby, the four rims could uniformly bear the loading force by the chip module D so as to avoid the warping due to non-uniform loading.
After being assembled completely, the electrical connector needs to be inspected through CCD for confirming whether the product is qualified. Before the electrical connector is inspected, the driving device C is rotated to be at an open state. The cover B moves toward the driving device C and then stops. The area B2 for accommodating pins and the area A2 for conducting and accommodating solder are therefore disengaged. The conducting circuit is at an open state. By the view from the bottom surface A3 of the body A along the direction F (vertical direction), the first rim B11 of the second rectangle hole B1 is exposed out of the corresponding edge of the body A to be a visible state (as shown in FIG. 2 and FIG. 3). In the inspection, the tin ball surface (i.e. the bottom surface A3) of the body A is inspected with an inspection light source. The inspection light source irradiates the first rim B11 of the second rectangle hole B1 of the cover B whose color is lighter than that of the body A (for the requirement of the industry or the consideration of appearance, the cover B is usually designed to be lighter than the body A). The first rim B11 is misjudged possibly to be the tin balls A23; the mistake is therefore made.
Therefore, there is a requirement for designing a new electrical connector so as to solve the above disadvantage.